IFR Fix: The ‘unexpected situation’

March 25, 2013

ifr fixWhat comes to mind on reading the words “IFR and stalls”?

Visceral reactions aside, probably very few IFR aviators would read that phrase, wave a hand in dismissal, and move on to more provocative subjects.

Likely even fewer insist that solid chunks of their proficiency flying focus on handling near-stall IFR scenarios, including while flying “under the hood.”

View-limited or not, what kinds of near-stall scenarios is an instrument pilot likely to confront?

The pilot of a Lancair 4 climbing through flights levels encountered quick-forming ice and nearly stalled; the aircraft was flying on the autopilot at the time. When a Piper PA-46 Malibu Meridian experienced landing-gear problems on an RNAV approach, distraction during the ensuing maneuvering caused a 200-foot altitude deviation, but decaying airspeed could have led to worse, said the pilot in an Aviation Safety Reporting System filing. In another, a Cessna Turbo Skylane canceled IFR six miles from the airport and opted for a straight-in approach “since I was already on that heading.” An aircraft presumed to be holding short took off instead, and the abrupt evasive maneuvering of the Cessna in a partial-flaps configuration elevated the stall/spin risk.

If a disconnect exists in pilots’ thinking between stalls and IFR, most instrument flying is conducted at angles of attack providing minimized exposure to the possibility of a stall encounter. (The exception typically dramatized in training is the nose-high unusual attitude recovery.)

The philosophy is the opposite of primary flight training, where the purpose of exploring slow flight, stall entries, and recoveries in various configurations is to avoid the hazards in everyday flying.

At the instrument pilot’s level, the goal, according to the Instrument Flying Handbook, is to “build confidence in a pilot’s ability to control the airplane in unexpected situations.”

While a primary flight student might flare too high on a normal landing, or lapse onto the back side of the power curve on final, the typical instrument approach is flown with greater margin. “An airplane with a stall speed of 50 knots (VSO) has a normal approach speed of 65 knots,” explains the Instrument Flying H andbook. “However, this same airplane may maintain 90 knots (1.8 VSO) while on the final segment of an instrument approach.”

Even then, wind shear or wake turbulence could turn an expected situation into one unexpected—so don’t let wariness about unknown risks make you complacent about those known.

Dan Namowitz

Dan Namowitz | Aviation Writer

Dan Namowitz is an aviation writer and flight instructor. He has been a pilot since 1985 and an instructor since 1990.